Parabolic focal coordinate formula
Definition of focus chord chord length formula of parabola in the field of geometry: If a straight line with inclination α passes through parabola focus F and intersects parabola at points A ... B, then the length of AB is 2P/(sinα)2 (that is, 2P divided by the square of sinα).
Hyperbolic focal coordinate formula
The focus is on the X axis (-c, 0) and (c, 0); The focus is on the y axis: (0, -c), (0, c). A hyperbola has two focal points, and the horizontal (vertical) coordinates of the focal points satisfy c = a+B. On the plane, the ratio of the distance from a given point to a straight line is a constant e (e((e >;; 1), that is, the eccentricity of hyperbola) is called hyperbola.
The focus is on the X axis (-c, 0) and (c, 0); The focus is on the y axis: (0, -c), (0, c). A hyperbola has two focal points, and the horizontal (vertical) coordinates of the focal points satisfy c = a+B. On the plane, the ratio of the distance from a given point to a straight line is a constant e (e((e >;; 1), that is, the eccentricity of hyperbola) is called hyperbola.
Elliptic focal coordinate formula
The coordinate formula of elliptical focal point is a 2-b 2 = c 2, where a is the length of major axis, b is the length of minor axis, and c is the focal length. If the long axis is on the X axis, the focal length is (c, 0), (-C, 0), and if the long axis is on the Y axis, the focal length is (0, c), (0, -C).
In mathematics, an ellipse is a trajectory in which the sum of the distances between two fixed points on a plane is constant. These two fixed points are called focal points.
Through this definition, draw an ellipse as follows: first, prepare a line and tie the two ends of this line to one point (these two points are regarded as the two focuses of the ellipse); Take a pen and tighten the thread. At this time, the two points and the pen form a triangle. Then pull the wire and start drawing, and keep the wire tight, and finally you can complete an oval shape.